The goal of the Centralized Histopathology Laboratory (CHPL) is to provide histologic services to investigators at M.D. Anderson Cancer Center. The CHPL supplies technical support and consultation, develops or applies appropriate techniques, and maintains the consistency and high quality needed to perform these techniques. The CHPL is currently located in the Department of Pathology in 375 feet/2. Because of the increasing emphasis on in vivo systems in cancer biology and developmental biology, the number of laboratories using tissue specimens, transgenic mice, and gene-knockout technologies has increased dramatically. To provide efficient histology services to the institution, the CHPL will be expanded, and a second 370- feet/2 laboratory will be located in the R.E. "Bob" Smith Research Building. The well-equipped and well-staffed CHPL processes fixed and frozen specimens for routine histologic analysis, immunohistochemical in situ hybridization (colorimetric procedures), and special staining for tissue sections and cells. The CHPL (both sites) is directed by Dr. Isaiah J. Fidler, and is accessible to all faculty, at M.D. Anderson Cancer Center, will preference given to investigators with peer-reviewed grants. Among the services provided are rapid preparation of high-quality standard histologic sections; application of special technologies as the need arises for selected projects, including preparation of frozen sections and histochemical, immunohistochemical, and tissue sections for in situ hybridization analysis; consultation with investigators to tailor technology to their special needs; and interpretation of histologic data. To access the CHPL, investigators make a formal application. After approval by the Director, the histotechnologist meets with the investigators to determine special needs of the study and the technical staff provides the histopathological services. The services are prioritized and coordinated to provide timely service. The development of new technologies that require additional equipment or special supplies has been funded by M.D. for specialized procedures such as in situ hybridization and 500 specially stained slides yearly. The increase in studies of transgenic mice and gene knockout mice will significantly increase the CHPL's workload, especially for special preparations such as serial sections of whole-embryos mounts. The CHPL is an essential component of the M.D. Anderson centralized research facilities that require histologic analysis.